Virtual reality, an entertainment and communication format that makes viewers feel like they’re in the middle of the action, may go mainstream this year, with a slew of companies bringing headsets to market.

The notable exception: Apple.

Apple’s chief device rivals Samsung and Google, as well as other tech giants like Facebook, have aggressively developed hardware to make VR more accessible, while Apple has remained silent.

However, other indicators suggest Apple has been quietly building a VR force. Earlier this week, the company confirmed it has hired a virtual-reality expert from Virginia Tech, following its hire of a audio engineer instrumental to Microsoft’s Hololens project, which shifts sound direction based on how you move your head.

Last month, Apple analyst Gene Munster at Piper Jaffray noted that Apple has hired more virtual- and augmented-reality personnel than Oculus-parent Facebook. The company has also acquired Metaio, a software company with VR patents, and PrimeSense, which designed the first motion sensors for Microsoft’s Xbox Kinect.

The Year in Vine: 10 Most-Looped Videos Include Ducks, Kids and Tragedy

Vine works best with perfectly timed comedic set-ups, like this howling-toy duck army.

Little kid wipe-outs are a recurrent theme.

Vines hit the jackpot when one person is the wrong place while another picks the right time to film.

Learning the value of pretending to like a birthday gift early on.

This aspiring basketball star crashing dunk was rewarded with 92 million loops.

Absurdity sometimes reigns on Vine. This clip has been looped more than 80 million times.

Vine is a popular app among young people, helping school-age feats of skill become a hit.

This kid's emotional confusion has attracted more than 95 million loops.